Stainless steel is widely used in our daily life, the appearance of this material is beautiful and durable. Next, I will answer a question about stainless steel: Will stainless steel rust?

First of all, we need to be clear that "stainless steel" is not absolutely rust free, but relative to other steel, it is not easy to rust. In the same environment, stainless steel has stronger corrosion resistance and corrosion resistance than other types of steel. Therefore, under normal circumstances, we can think that stainless steel will not rust. However, if the use or maintenance of stainless steel is improper, or its environment is too harsh, then stainless steel may rust.

Stainless steel has the ability to resist atmospheric oxidation, which is what we often say is stainless. At the same time, it also has the ability to resist corrosion in an environment containing acid, alkaline and salt, which is what we call corrosion resistance. However, the corrosion resistance of stainless steel will change with the chemical composition of the steel itself, the protection state, the conditions of use and the type of environmental media.

Taking 304 steel pipe as an example, in a dry and clean atmosphere, it has very excellent corrosion resistance. However, if it is moved to the seaside area, it will rust quickly in the sea fog containing a lot of salt. In contrast, 316 steel pipe performance is very good. Therefore, we cannot simply think that any kind of stainless steel can resist corrosion and does not rust under any environment.

The reason why stainless steel can resist corrosion is mainly because its surface forms an extremely thin and solid stable chromium-rich oxide film (also known as a protective film). This layer of film can prevent the continued infiltration and oxidation of oxygen atoms, thus giving stainless steel the ability to resist corrosion. However, once this film is destroyed for some reason, the oxygen atoms in the air or the oxygen atoms in the liquid will continue to penetrate into the metal, or the iron atoms in the metal will continue to resolve out, forming loose iron oxide, so that the metal surface is constantly corroded.

In daily life, we commonly damage the surface film in several ways include:

The surface of stainless steel is attached with dust or exotic metal particles containing other metal elements, in the humid air, the condensate between these attachments and stainless steel will form a micro battery, causing an electrochemical reaction, thereby destroying the protective film, this phenomenon is called electrochemical corrosion.

The surface of stainless steel is adhered to organic juices (such as melons and vegetables, noodle soup, sputum, etc.), in the case of water oxygen, these substances will form organic acids, which will cause corrosion to the metal surface for a long time.

The surface of stainless steel is adhered to substances containing acids, alkalis and salts (such as soda water and lime water splashing on the decoration walls), which can cause local corrosion.

In polluted air (such as the atmosphere containing a large number of sulfides, carbon dioxide, nitrogen oxide), condensed water will form sulfuric acid, nitric acid, acetic acid liquid points, causing chemical corrosion.

In order to ensure that the metal surface is permanently bright and not corroded, we have the following suggestions:

It is necessary to clean and scrub the decorative stainless steel surface frequently to remove attachments and eliminate external factors that cause modification.

In the seaside area, 316 stainless steel should be used, because 316 material can resist seawater corrosion.

The chemical composition of some stainless steel pipes on the market cannot meet the corresponding national standards, and cannot meet the requirements of 304 material. Therefore, it will also cause rust, which requires users to carefully choose the products of reputable manufacturers.

Next, I will introduce the characteristics of 316 stainless steel for you:

1. corrosion resistance: 316 stainless steel corrosion resistance is better than 304 stainless steel, it can resist the erosion of the ocean and aggressive industrial atmosphere.

2. heat resistance: 316 stainless steel has good heat resistance, in the continuous use below 1600°C -1700°C, has good oxidation resistance. In the range of 800-1575C, it is best not to continuously work 316 stainless steel, but in the continuous use of 316 stainless steel outside this temperature range, the stainless steel has good heat resistance.

3. heat treatment: 316 stainless steel heat treatment performance is good, in the range of 1850-2050°C annealing, can be quickly annealed and cooled, can not be overheated treatment hardening.

4. welding: 316 stainless steel welding performance is good, can be welded by standard welding method, so that the installation is more convenient.